Comminuting mill



July 6 9 19260 R. c. NEWHOLJSE COMMINUTING MILL Filed June 9, 1921 2Sheets-Sheet 1 IHI Jufly 8 9 19260 159L941 R. c. NEWHOUSE COMMINUTINGMILL Filed June 9, 1921 2 Sheets-Sheet 2 I Patented July 6,4226.

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BAY C. NEWHOUSE, h 'WAUWATDSA, WISCONSIN, ASSTGNOR TO ALLIS-CHALMERSMANUFACTURING COMIANY, 0F MILWAUKEE, WISCONSIN, A CORIPORATION Q1?DELAWARE.

" COMMINU'IING MILL.

Application filed June 9, 1921. Serial N0. 476,136.

-. This invention relates in general to improvements in the art ofreducing solidsubstances of various kinds by impact and abrasion, andrelates more specifically to 5 improvements in the construction andoperation of rotary comminuting mills for d1sintegrating materials withthe aid of a plurality of freely cascading bodies.

An object of the invention is to provide a comminuting mill which issimple in construction and eflicient in operation. Another object of theinvention is to provide efiicient means for removing reduced materialfrom a comminuting mill.

It has been discovered in operating rotary comminuting mills of the typewhich utilize freely tumbling comminuting bodies as a pulverizingmedium, that considerableavailable energy is wasted due to thecushioning 2 of the cascading bodies, by the material whichds inpulverulent condition. This fine material lodges upon the comminutingbodies and packs in the voids between these bodies and around the largerparticles of 2 material which require further reduction,

thereby preventing the tumbling comminuting bodies from efieotivelypulverizing the larger particles in the charge, and also preventing freedelivery of the comminuted material from the charge.

In order to avoid such undesirable cushioning of the comminuting bodies,and also in order to enhance the capacity of mills of this type, thepresent invention contemplates material. With the present invention thefine particles of the material are removed from various places along thelength of a mill, pneumatically, that is with the aid of a blast of airor other elastic fluid. The pneumatic removal of the material is mademore effective by the provision of chambers which are free fromcomminuting bodies, and through which the material passing from onestage of the mill to another is showered. The capacity of a millconstructed in accordance with the present invention is further enhancedby the provision of mechanical means in addition to the pneumatic means,for removing material from the mill. While the mill illustrated hereinand embodying the present invention is especially adapted for thereduction of fuel such as coal, it is not desired to limit the inventionto such application.

rapid removal of the sufiiciently comminuted Some of the novel featuresof comminuting mill construction herein shown and described but notspecifically claimed, form the subject of copending application S. N.188,258, filed August 23, 1917.

A clear conception of several embodiments of, the present invention andof the operation of a mill constructed in accordance therewith, may behad by referring to the draw- ,ings accompanying and forming a part ofthis specification, in which like reference char acters designate thesame or similar parts in the various views.

Fig. 1 is a central vertical section through a multi-stage rotarycomminuting mill embodying means for showering material betweensuccessive stages of the mill.

Fig. 2 is a transverse vertical section through the rotary multi-stagecomminuting mill, part of the section being taken 75 through one of thecomminuting chambers and another partof the section being taken throughone of the showering chambers.

Fig. 3 is a diagrammatic side elevation illustrating the application ofthe new comminuting mill in a powdered fuel distributing system.

Fig. 4 is a fragmentary central vertical section through another form ofmulti-sta'ge rotary comminuting mill embodying features of theinvention.

The combination or multi-stage comminuting mill disclosed in Figs. 1 and2, comprises in general a rotary cylindrical casing" 1 illustrated ashaving uniform diameter throughout its length, the casing being providedwith feedand discharge end heads 2, 3 respectively, and having therein as'er1es of partitions or division heads 8, 9, 10 winch divide the casing1 into successive stages or comminuting chambers 4, 5, 6, 7respectively. The successive comminuting chambers 4, 5, 6, 7 havetumbling comminuting bodies 11, 12, 13, 14 of gradually decreasing sizestherein, the largest comminuting bodies 11 being 100 located in thecoarse grinding chamber 4 and the smallest comminuting bodies 14 beinglocated in the finishing chamber 7. The mill is rotatably mounted insuitable end bearings which embrace the feed and'dischargetruncomminuting chambers formed by the easing 1, is rovided with liners30 and each of the cham rs 4, 5, 6, 7 is preferably provided with aremovable cover 29 for permltting independent access to the interior ofany one of the chambers of the mill. The feed end of the mill isprovided with a mechanical feeder 15 for introducin v the material whichis to be reduced, into the inlet end of the coarse grinding chamber 4through the feed trunnion. The feed end of the mill is also providedwith suitable openings 17 which may be adjustable in size, for adm1tting air or other elastic fluid to the interior of the mill.

Each of the partitions or division heads 8, 9, 10 comprises a pair ofparallel walls spaced apart to form an intermediate showering chamberwhich is free from comminuting bodies. Each of the walls of a divisionhead is provided with a multiplicity of openings 18 which are of suchsize that they will permit material to freely enter and leave theshowering chamber from and to the adjacent comminuiting chambers, butwill not permit the comminuting bodies to enter the showering-chamber.Within each of the showering chambers is located a plurality of radialconducting vanes 26 and a plurality of T shaped project-ions orprecipitators 27 which during normal operation of the mill are adaptedto elevate the material delivered into the lower portion of theshowering chamber and to precipitate or shower this material downwardlythrough the showering chamber and upon the conducting vanes 26. Theinner extremities of the conducting vanes 26 terminate adjacent to acentral conducting cone the apex of which extends toward a dischargeopening 25 in the division head.

The discharge end of the finishing chamber 7 of the mill disclosed inFig. 1 is rovided with a perforated plate 19 whic is spaced from the endhead 3. Located within the space between plate 19 and the end head 3 isa series of elevating vanes 20 each of which is provided with arelatively large opening the size of which is adjustable by means of aradially slidable adjusting plate 31. The inner extremities of theelevating plates 20 are located in proximity to a central finaldischarge cone the apex of which is directed toward the dischargetrunnion 21.

The discharge end of the finishing chamber 7 of the mill disclosed inFig. 4 is provided with a rforated division plate 38 spaced from t eperforated plate 19 and forming a showering chamber 39 similar to theshowering chambers in the division heads. The central portion of theplate 19 is provided with a return cone having its apex directed towardthe finishing chamber 7 and surrounded by a central rejects returnopening 40. The perforated plate 19 is spaced from the end head 3, thespace between these elements bein free from elevating vanes. The mediaportion of this final discharge space or chamber is provided with acentral discharge cone having its apex directed toward the dischargetrunnion 21 as in the mill disclosed in Fig. 1.

In the diagram illustrating the application of the new comminuting millin a powdered fuel distributing system, as shown in Fig. 3, the finaldischarge from the trunnion 21 is delivered into an initial separatingchamber 22. From this initial separator the coarser particles ofmaterial are delivered by gravity through a dischar e spout 23 into ahorizontal conveyor 35. T e finer particles of material are carried bythe air blast throu h a discharge conduit 24 and are delivered into acyclone separator 32. The relatively coarse material removed from thedust laden air by the separator 32 is delivered by gravity through aconduit or spout 34 into the conveyor 35, while the air which stillcontains considerable fine material, is delivered to a bag type of dustcollector 36 through a conduit 33. The pure air is withdrawn from thefinal separator 36 by means of a suction fan 37, this fan serving tocreate the flow of air through the entire system. The fine particles ofmaterial removed by the dust collector 36 are delivered by avity to theconveyor 35 where they ming e with the particles of material previouslyremoved, and from which all of the material is delivered to the desiredpoint of utilization.

During the normal operation of the mill disclosed in Figs. 1 and 2, theraw material is admitted to the coarse grinding chamber 4 by the feeder15, the suction fan 37 having been first placed in operation androtation having been imparted to the shell 1 by means of the gear 28. Asthe material falls into the mill, the sufficiently fine particles areimmediately removed and are carried away by the blast of air enteringthrough the opening 17. The remaining material which requires furtherreduction is initially reduced during its passage through the coarsegrinding chamber 4 by the tumbling and rubbing action of the largecomminuting bodies 11. At the discharge end' of the chamber 4, materialis delivered into the first showering chamber located within-thedivision head 8. The material thus admitted to the first showeringchamber is elevated by the precipitators 27 and during rotation of themill, is showered toward the conducting vanes 26. The air blast passingthrough the chamber 4 enters the first showering chamber through theopenings 18 and passes through the falling material delivered from theprecipitators 27. During this transgression of the air blast the finethe air blast and upon the conducting vanes carried from the showeringparticles of material are removed and are chamber through theperforations in the secondwall of the division head 8. The relativelycoarse particles of material drop through 26, and are delivered throu vhthe opening 25 into the second grinding c amber 5. Due to the passage ofair throu h the relatively small perforations below t e central opening25, the delivery of material to the second comminuting chamber 5 isgraded, that is, the coarser particles of material are depositeddirectly adjacent to the partition 8 while the finer particles arecarried along the mill by the air blast and are delivered into thechamber 5 more remotely from the partition 8, thus admitting theparticles to different portions of the chamber 5 1n accordance withtheir relative sizes.

The coarser articles of material-are further reduced w ile passingthrough the second comminuting c amber 5 by the tumbling nuting bodies12. At the discharge end of the chamber 5 material is delivered into thesecond showering chamber located within the division head 9. Thematerial thus admitted .to the second showering chamber is elevated bythe precipitators 27 therein, and is showered as in the previousshowering compartment. The air blast passing throu h the chambers 4: and5 enters the second s owering chamber through the openings 18 and passesthrough the falling material thereby removing the fine particles andcarrying them from this showering chamber through the perforations inthe discharge wall of the division head 9; The

remaining relatively coarse particles of material drop through the airblast and upon the conducting vanes 26 and are delivered through theopening 25 into the third comminutmg chamber 6. As in the case of thedelivery to the preceding chamber 5, the

- admission of material to the third comminuting chamber 6 is againgraded.

The remaining coarse particles of material are further reduced whilepassing through the third comminuting chamber ,6 by the tumbling andrubbing action of the comminuting bodies 13.' At the discharge end ofthe chamber 6 material is delivered into the third showering chamberlocated within the division head 10. The material thus admitted to thethird showering chamber is elevated by the precipitators 27 therein, andis showered as in the preceding showering compartments. The air blastpassing through the chambers 4, 5, and 6 enters the third showeringchamber through the openings 18 and passes through the falling materialthereby removing additional fine particles and carrying them from thisshowering chamber through the perforations in and rubbing action of thecommithe discharge wall of the division head 10. i

The remaining relatively coarse particles of material drop through theair blast and upon the conducting vanes 26 and are delivered through theopening 25 into the fourth or finishing chamber 7. As in the case of thedelivery 'to the preceding chambers 5 and 6, the admission of materialto the finishing chamber is again graded.

In the finishing chamber 14 the material is finally comminuted by thetumbling and rubbing action of the comminuting bodies 14. The materialis finally delivered from the finishing chamber 27 through theperforations in the plate 19 and" is deposited into the path of theelevating vanes 20.

These vanes elevate the finished product and eventually deposit the sameupon the final discharge cone which conducts the material It will benoted that the air blast passing I through the material delivered fromthe feeder 15 into the initial grinding compartment 4 willalso to someextent, grade the delivery of material from the feeder 15 to thecompartment 4. By thus grading the admission of material to the chargesin the several grinding compartments 4, 5, 6, 7, the coarserparticlesare more efiiciently reduced due to the absence of finematerial from the portion of the charge to which they are admitted, Theair blast passing through the mill also has a sweeping action upon thecharges in the several compartments thereby enhancing the milleliiciently by removing the fine material which would otherwise tend tocushion the cascading comminuting bodies. This air blast will obviouslybecome more and more saturated with fine material as it advances throughthe mill, and the amount of material which it is capable of removingwill be dependent upon the velocity and volume of air contained in theblast.

The adjustable plate portions 31 of the elevating vanes 20 serve topermit retention and reduction of material within the mill for a longerperiod of time. In the mill disclosed in Fig. 4 the elevating vanesdivision wall 38, returns the over-size mano i terial to the finishingchamber 7 thereby positively insuring complete reduction of all of thematerial. With the mill disclosed in Fig. 1, the discharge product willun doubtedly contain some relatively large particles but such over-sizematerial is not objectionable when reducing coal and other fuel adaptedfor use in powdered fuel heating installations.

It will be obvious that a mill constructed in accordance with thisinvention will to a large extent, avoid undesirable cushioning of thecomminuting bodies and will have relatively great capacity due toremoval of fine material at various points along the mill. The pneumaticremoval affords a simple and efficient method of removing and ofsubsequently conveying the material from the .mill. The showeringchambers which are free from comminuting bodies enable the air blast toeffectively remove the fine particles and also provide simple means forgrading the delivery of material to the successive comminuting chambers.While the mill has been disclosed as embodying four separate comminutingchambers, it will be understood that this number may be increased ordiminished in accordance with objects to be accomplished. 1

It should be understood that it is not desired to limit the invention tothe exact details of, construction and of operation herein shown anddescribed, for various modifications within the scope of the claims mayoccur to persons skilled in the art.

It is claimed and desired to secure by Letters Patent 1. In combination,a rotary drum, walls dividing said drum into a series of chambers, thesuccessive walls having perforations providing an annular series ofsubstantially rectilineal passages extending throughout the lengthof.sa1d'drum,-comminuting bodies located only in alternate chambers ofsaid series, means for causing a blast of gas to flow through saidpassages,

and means for showering material through said blast within saidintermediate chambers.

2. In combination, a drum rotatable about an axis and having uniformdiameter throughout its length, parallel walls dividing said drum into aseries of chambers, the successive walls having perforations roviding anannular series of substantially rectillneal unobstructed passagesextending parallel to said axis and throughout the length of said drum,comminuting bodies of graded size located only in alternate chambers ofsaid series, means for causing a blast of gas to flow through saidpassages, and precipitators for showering material through said blast.within said intermedi ate chambers.

3. In combination, a drum rotatable about a horizontal axis, transversewalls dividing said drum into a series of chambers, the successive wallshaving perforations providing unobstructed rectilineal passagesextending parallel to said axis and throughout the length of said drum,comminuting bodies located only in alternate chambers of said series,means for causing a blast of gas to flow through said passages above thelevel of said bodies, and means for showering material through saidblast within said intermediate chambers.

4. In combination, a drum rotatable about an axis, transverse wallsdividin said drum into a series of chambers, all 0 said walls havingperforations providing a separator for receiving material dischargedfrom said drum, and common means for causing a blast of gas to flowthrough said passages and said separator in succession.

- In testimony, whereof, the signature of the inventor is afiixedhereto.

RAY o. NEWHOUSE.

